I have had my Pro2 since December and nearly every time I change the filament I have to take off the filament sensor. This is because as I remove the filament a blob is created at the end. Off goes the sensor so I can snip off the end. Nearly every time!!! If the sensor was on the frame of the printer it would be much easier to manage.

Maybe try Unloading with a bit lower Temperature, so that the filament doesn't melt up that much.Or try the other way around, heating up higher to melt the filament even more, so that the filament is ripped of the large blob in the nozzle. This could require more priming after loading the new filament..